Fabrication of Two-Dimensional Polymers and Two-Dimensional Materials Dissertation zur Erlangung des Grades „Doktor der Naturwissenschaften“ am Fachbereich Chemie, Pharmazie und Geowissenschaften der Johannes Gutenberg-Universität Mainz vorgelegt von Martin Gerhard Christian Pfeffermann geboren in Offenbach am Main Mainz, 2016 Dekan: 1. Berichterstatter 2. Berichterstatter Tag der mündlichen Prüfung: II Die vorliegende Arbeit wurde in der Zeit von Mai 2013 bis April 2016 am Max-Planck-Institut für Polymerforschung in Mainz im Arbeitskreis von Prof. Dr. Klaus Müllen angefertigt. D77 III IV Meiner Familie V VI Table of Contents Abbreviations .............................................................................................................. IX 1. Motivation .............................................................................................................. 1 2. Two-Dimensional Supramolecular Polymers ......................................................... 7 2.1. Introduction .................................................................................................... 7 2.1.1. CB[8] complexes ..................................................................................... 8 2.1.2. Metal-Ligand Complexes ....................................................................... 11 2.1.3. Two-Dimensional Supramolecular Polymers ......................................... 11 2.1.4. Analysis of Two-Dimensional Supramolecular Polymers ....................... 13 2.2. Target Objective ........................................................................................... 16 2.3. Two-Dimensional Supramolecular Polymers Based on Host-Guest Enhanced Donor-Acceptor Interactions ......................................................................... 17 2.3.1. Assembly in Aqueous Medium .............................................................. 17 2.3.2. Assembly at the Toluene-Water Interface ............................................. 29 2.3.3. Assembly at the Air-Water Interface ...................................................... 74 2.3.4. Summary .............................................................................................. 79 2.4. Two-Dimensional Supramolecular Polymers Based on Metal-Organic Interactions .................................................................................................. 81 2.4.1. Synthesis .............................................................................................. 82 2.4.2. General Procedure for the Self-Assembly of Metal-Organic Layers at the Water-Air Interface ................................................................................ 83 2.4.3. Morphological Characterization ............................................................. 84 2.4.4. Structural Characterization .................................................................... 86 2.4.5. Application as Active Material in the Hydrogen Evolution Reaction ....... 95 2.4.6. Summary .............................................................................................. 98 3. Hollow Carbon Tubes ........................................................................................ 101 3.1. Introduction ................................................................................................ 101 3.1.1. Structure and Conductivity of Graphite ................................................ 103 VII 3.1.2. Raman Spectroscopy on Graphite Materials ....................................... 105 3.2. Results and Disscussion ............................................................................ 106 3.2.1. Solution-Based Approaches ................................................................ 106 3.2.2. Vapor-Based Approach ....................................................................... 108 3.3. Summary ................................................................................................... 123 4. Disulfide-Bridged Coronenes for Li-S batteries ................................................. 125 4.1. Introduction ................................................................................................ 125 4.2. Results and Discussion .............................................................................. 128 4.2.1. Per(disulfide)coronene as Small Molecule Cathode Material in Li-S Batteries ............................................................................................. 128 4.2.2. Randomly Disulfide-Bridged Persulfocoronene as Polymer Cathode Material in Li-S Batteries ..................................................................... 138 4.3. Summary ................................................................................................... 146 5. Conclusion and Outlook .................................................................................... 147 6. Experimental Part ............................................................................................. 155 6.1. Materials .................................................................................................... 155 6.2. Methods ..................................................................................................... 155 6.3. Synthesis ................................................................................................... 167 7. References ....................................................................................................... 188 8. List of Publications ............................................................................................ 207 9. Curriculum Vitae ............................................................................................... 209 10. Acknowledgement ......................................................................................... 211 VIII Abbreviations Abbreviations 2D two-dimensional 2DP two-dimensional polymer 2DSP two-dimensional supramolecular polymers AFM atomic force microscopy BET Brunauer-Emmett-Teller CB[n] cucurbit[n]uril CNT carbon nanotube D-A-CB[8] donor-acceptor-cucurbit[8]uril DCM dichloromethane DLS dynamic light scattering DME 1,2-dimethoxyethane DOL 1,3-dioxolane DOSY diffusion-ordered spectroscopy EDX energy dispersive X-ray spectroscopy GIWAXS grazing incidence wide angle X-ray scattering HBB hexabromobenzene HBC hexa-peri-hexabenzocoronene HER hydrogen evolution reaction HETCOR heteronuclear correlation spectroscopy HOPG highly oriented pyrolytic graphite HSQC heteronuclear single quantum coherence IR infrared spectroscopy ITC isothermal titration calorimetry LB Langmuir-Blodgett LG Lee-Goldberg LiTFSI lithium bis-trifluoromethanesulfonylimide IX Abbreviations NMR nuclear magnetic resonance spectroscopy NOESY nuclear Overhauser enhancement spectroscopy OM optical microscopy PAH polycyclic aromatic hydrocarbon PCC perchlorocoronene PTFE poly(tetrafluoro)ethylene PXRD powder X-ray diffraction Ref. reference REPT-HDOR recoupled polarization transfer heteronuclear dipolar order RHE reference hydrogen electrode SAED selected area electron diffraction SAXS small-angle X-ray scattering SEM scanning electron microscopy STM scanning tunneling microscopy TEM transmission electron microscopy UV/Vis ultraviolet-visible spectroscopy XPS X-ray photoelectron spectroscopy XRD X-ray diffraction X 1. Motivation 1. Motivation In 2004, Novoselov and Geim received the Nobel Prize for “groundbreaking experiments regarding the two-dimensional material graphene”[1]. Prior to their achievement of isolating single-layer graphene sheets, it was believed that two- dimensional polymers (2DPs) were not stable, as a layer spread into two dimensions was considered entropically unfavored.[2] Nevertheless, even more important than the general accessibility of 2DPs were the outstanding properties measured in graphene, namely a high electron mobility of 200 000 cm² V-1 s-1,[3-4] ballistic electron transport over ~0.4 µm,[5] a quantum Hall effect at room temperature,[6-7] a large specific surface area of 2630 m² g-1,[8] a Young’s modulus of ~1.0 TPa,[9] and a high thermal conductivity of ~5000 W m-1 K-1.[8] Most of these properties were traced back to its two- dimensionality, triggering research in the field of both inorganic as well as organic two- dimensional (2D) materials, which is steadily increasing ever since. When discussing 2D structures, it is important to define and distinguish the terminology used in literature, as it includes an extensive number of different structural occurrences, morphologies, properties, and applicabilities, all correlated to the dimensionality of the provided material. Although their expressions are sometimes randomly used throughout the literature, 2D monolayers will be addressed as two- dimensional polymers (2DPs), and two-dimensional supramolecular polymers (2DSPs) as subcategory, respectively, according to the definition of Schlüter et al.[10] This definition implicates the presence of a well-ordered structure of connected monomer units in only two orthogonal directions. The remaining materials, consisting of an ensemble of lamellar structures of bi-, tri-, or multilayers will be referred to with the general term 2D material as conventionalized by Feng et al[11] or Payamyar et al.[12] When discussing both 2DPs and 2D materials, the generalizing term 2D structures will be used. The field of 2D materials is well-developed and includes a large number of materials, both naturally occurring and synthetically produced. For example, both graphite and mica can be found in nature and exhibit lamellar structures.[13]